Float switch



M. E. HENNING Dec. 19, 1933.

FLOAT SWITCH Filed April 14, 1950 daveulo'r -J7Zalcahll 2': Hex 2121 1Patented Dec. 19, 1933 PATENT OFFICE FLOAT SWITCH Malcolm E. Henning,Des Moines, Iowa, assignor to Penn Electric Switch 00., Des Moines,Iowa,

a corporation of Iowa Application April 14, 1930. Serial No. 444,201

9 Claims.

The object of my invention is to provide a float switch which is simple,durable and comparatively inexpensive to manufacture.

A further object of my present invention is to provide a float switchconsisting of a casing with a pair of electrical contact prongsextending therefrom to which a plug may be applied for connecting theswitch in an electric circuit.

Still a further object is to provide a switch l0 within the casing andmeans operated from a float outside of the casing for actuating theswitch therein.

Still another object is to provide in the casing a switch structurehaving an armature arm with a spring acting thereon to pull it in onedirection and a magnet to pull it in an opposite direction, the spaceprovided for the throw of the armature arm being such thatthe arm willnormally remain adjacent the magnet when moved to such position and willremain spaced from the magnet when moved to such position.

Still a further object is to provide an operative connection extendingthrough .a bearing bushing and connected with the switch on the insideof the casing and with a float on the outside of the casing, the bearingbushing extending through an opening in the wall of the casing.

With these and other objects in view my invention consists in theconstruction, arrangement and combination of the various parts of mydevice, whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims, and illustrated in theaccompanying drawing, in which:

Figure 1 is an end elevation of the float switch structure showing itapplied to a liquid tank, the tank being shown in section and afloatbeing 11- lustrated in connection with the switch structure; the switchstructure being connected with a pump which is shown diagrammatically.

Figure 2 is a side elevation of the switch structure with the coverthereof removed,

Figure 3 is a sectional view on the line 3-3 of Figure 2.

Figure 4 is a sectional view on the line 4-4 of Figure 3.

Figure 5 is a. sectional view on the line 5-5 of Figure 2 and Figure 6is an enlarged sectional view on the '60 Mali-801M034.

0n the accompanying drawing I have used the reference numeral 10 toindicate a liquid tank or the like. A float switch structure A ismounted thereon and includes a casing 12 provided with a 65 cover member14. Screws or the like 18 may be used for connecting the casing 12 withthe tank 10. A bearing sleeve 18 is mounted through an opening 20 in oneend of the casing 12 and retained in position by a nut 22. A shaft 24extends rotatably through the sleeve 18. A float 1 arm 26 is connectedwith the shaft 24 and terminates in an eye 28. A float 30 is attached toa float rod 32 which extends through the eye 28. Lock nuts 34 areprovided on the float rod 32 above and below the eye 28 for adjustingthe operation of the switch A relative to the high and low levels of theliquid 36 within the tank 10. An opening 38 is provided in the tank 10for the float rod 32 and a bracket 40 is provided to guide the floatrod.

Within the casing 12 a pintle 42 is suitably supported and a switch arm44 is pivoted thereon. The switch arm is provided with a resilient leafspring arm 48 which is operativelyconnected by a link 50 to an arm 52 onthe shaft 24. A clamp screw 54 is provided for clamping the arm 52 on 13;; the shaft 24, the arm being split as best shown in Figure 4.

A magnet 56 acts upon the arm 44 to pull it in a circuit closingdirection. A spring 58 acts in opposition to the magnet 56. The spring58 has one end connected with a cotter pin which forms the pivotalconnection between the upper end of the link 50 and the arm 52.

Its opposite end embraces a sleeve 60 which may be adjusted toward oraway from the upper wall of the casing 12 by rotating a screw 62 whichis screw threadedly mounted in the sleeve 60. Thus the tension of thespring 58 may be adjusted. A lock nut 64 is provided for the screw 62.

A flexible lead 66 extends from the switch arm 44 to a contact prong 68(see Figure 5). A second contact prong 70 is electrically connectedthrough a screw '72, spring 74 and nut 76 with a contact plate 78. Astationary contact 80 is 5. carried by the plate 78 and coacts with acontact 82 extending through an opening in the arm 44 and connected witha leaf spring 84, all as clearly set forth in my co-pending application,Serial No. 426,677, filed January 27, 1930.

Practical operation In the operation of my device,' the parts to be inthe position illustrated in Figure 2, the switch is in clam circuitposition so that electric current will flow through the pump motor 86shown diagrammatically in Figure 1. This operates the liquid pump 88 forpumping liquid into the tank 10. The rising liquid raises the float 30until the lower lock nuts 34 engage the 1 eye 28 and swing the arm 26upwardly. Such upward swinging of the arm 26 will raise the left handend of the resilient arm 48 (see Figure 2) until it has been bent tosuch an extent to overcome the magnetic influence of the magnet 56 tohold the arm 44 in closed circuit position. The arm will then movetowards open circuit position picking up the spring 48 as it does sowhereupon the contacts 80 and 82 will become quickly separated.

Another thing hastening separation is that the arm 44 immediately uponmoving away from the magnet 56 is in a weaker magnetic field. The

spring 58 will then retain the switch arm in open position until thelevel of the liquid 36 lowers to a predetermined point whereupon'theupper lock nuts'34 will engage the eye 28 for swinging the arm 26downwardly, closing the switch and again starting the pump 88.

The magnet 56, as the arm 44 moves towards it, acts with ever increasinginfluence on the arm while as the arm moves in an opposite direction theinfluences of both the magnet and the spring 58 decrease but themagnetic influence decreases in greater proportion than' the springinfluence. The result is a switch in which the arm 44 will stay ineither of the positions to which it is moved and the two-way-resilientarm 48 always insures that the switch arm will quickly move from oneposition to another. The tension of the spring 58 may be varied toinsure the operation just described, it being adjusted to compensate forthe weight of the arms 26 and 52. The switch is illustrated on thedrawing as being in connection with a float merely by way ofillustration. A

Other'control devices may be made for the switch and the switch may bereversely arranged whereby toopen a circuit when the level of the liquidlowers if desired without departing from the real spirit and purpose ofmy invention, and

it is my intentionte cover by my claims, any

modified .forms' of structure or use of mechanical equivalents, whichmay be reasonably included within their scope. D

I claim as my invention:

1. In a switch structure, a movable switch arm,

a movable actuating member, a link connection between said actuatinmember and said switch arm, said switch arm being arranged to normallystay in either closed or open circuit position when moved to assume saidposition and a spring counterbalancing the weight of said actuatingmember so that such weight does not move the switch arm from one of itsassumed positions to the other one.

2. In a switch structure, a switch casing, a stationary contact therein,a pivoted switch arm, a contact carried thereby for coaction with saidstationary contact, amovable actuating member, a spring counterbalancingthe weight of said member and a leaf spring having one end secured tosaid switch arm and its other end operatively connected with saidmember.

3. In a switch structure, a stationary contact,

4. In a switch structure, a movable switch arm,

a magnet adjacent said switch arm and'tending to exert a pull in anupward direction thereon to retain said switch arm in raised positionbut not sufficient to raise it when in lowered position, a movableactuating member connected with said switch arm and a spring tending tocounterbal- I ance the weight of said actuating member so that it, whenfree, will permit said switch arm to ree main in either'of saidpositions. 5. In a switch structure, a movable switch arm, a magnetadjacent said switch arm and tending to exert an upward pull thereon, atwo .po'sition actuating member connected with said switch arm and aspring connected with said actuating member and tending to move the samein a direction to counterbalance the weight of said actuating member sothat when said switch arm is moved to either its raised or its loweredposition it will remain therein until moved by the actuating member toits other position.

6. In a switch structure, a stationary contact, a movable switch armhaving a contact for coaction therewith, a magnet adjacent said switcharm and tending to exert a pull thereon to engage said contacts witheach other, a movable actuating member, adjustable spring means tocounterbalance the weight of said member and a leaf spring having oneend connected with said nected with said member.

'7. In a switch structure, a pivoted switch arm, a movable actuatingmember, a spring counterbalancing the weight of said member, a leverseswitch arm and its other end operatively conv c'ured to said controlshaft and a leaf spring having one end secured. to said switch arm andits other end operatively connected with said memher.

8. In a switch structure, a movable switch arm, magnetic means tendingto cause movement thereof in one direction, a movable actuating member,a leaf spring having one end connected to said switch arm, a linkconnection between the other end of said leaf spring and said member anda spring counterbalancing the weight of said actuating member.

9. In a switch structure,- a movable switch arm, a magnet adjacent saidswitch arm and tending to exert a pull thereon in one direction, amovable actuating member, adjustable spring means to counterbalance theweight of said actuating member and a leaf spring having one endconnected with said switch arm and its other end operatively connectedwith said actuating member. I

MALCCLM E. HENNING.

